This manga is about the relationship between two sisters... one in junior high and the other age 4 and their father. Due their mother's death, the older girl sometimes has to take care of her sister while the father works. Sometimes the older one gets frustrated but she doesn't really mind this because she loves her little sister. Basically this is a junior high school story and the stories that the girls go through have either a moral or a lesson to tell.
Personal Thoughts:
KUJIRA NO OYAKO
Overall it's a sweet story. Some parts brought tears to my eyes! ... guess it's just because I'm sentimental... The most noteworthy part is seeing the younger girl grow up and become more inquisitive of the world.
In volume 5, there is a side story about how the parents got together. Frankly, I thought the drawings were a bit off and crude and the subject has been reused many times before. It's could have been done better, but what the heck do I know?